Thomas bttdlt jeeey



Aug. 7, 1928.

Filed June 24, 1926 .Ivillnmv :Blc

gw w and only insulators of the `visuallgf Patented Aug. 7, 1928.

UNITED STATES THOMAS DUDLY BERRY, OF MARKDALE, ONTARIO, CANADA.

DEVICE FOR LOCATING DEFECTIVE INSULATORS IN ELECTRIC POWER LINES.

Application led .Tune 24, 1 928. Serial No. 118,297.

It is necessary from time to time to inspect insulators of power lines for the purpose of locating defective or damaged insulators. It has been usual to shut off the power and then have linemen climb the poles or towers and inspect the insulators or by tapping the same. This metho is slow as well as more or less dangerous for the lineman, and there is further the Aadded objection of interfering with the service through the shutting oill of the power.

Lately an instrumentv has been tried out which is used by engaging it with the insulator, which instrument 1s adapted to give audible indication of a power leak through the insulator.

This instrument, however, adjusted before starting out on the days work by testing it on' a good and a bad insulator of the same kind. However, as insulators of different kinds are employed, kind'for which the instrument is adjusted can be satisfactoril tested, it is necessary to return to the ase and re-adjust the instrument and again go over the ground.

Further, it is found that atmospheric conditions, such as the amount of moisture in the air, adjustment of the. instrument and, therefore, for exam le, a setting of the instrument made ear y in the morning when the dew is on the ground will not give the Same results later on in the day when the sun is shining bri htly. This is due mainly to the diiferent characteristics of the insulators due 'to the varyin humidit It will be seen t erefore t at the instrument referred to will, if adjusted for a pai'- ticular case, indicate whether an insulator is defective or not, but. it is not satisfactory for general use on account of the changing atmospheric conditions and on account. of the different types of insulators used on a power line.

My object therefore is to devise an instrument for locating defective insulators which may be adjusted on the spot, to suit the di erent atmospheric conditions met with in the course of the day, and which may also be adjusted on the spot as dil'erent types of insulators are encountered and which may also be adjusted on the spot to suit the different line voltages encountered.

requires to be have an important bearing in the A further object is to devise means whereby the leaka may be detected, rectified and amplified into audible sounds by m instrument which sounds may be hear in the open at some distance from the insulator itself and without the use of ear hones as used with the instrument above regerred to.

I attain my object by means of the constructioris hereinafter described and illustrated in the accompanying drawings in which:

Fi 1 is a longitudinal section through my etector;

Fig. 2 a section on the line 2-2 in Fig. 1; 1 Fig 3 a section on the line 3-3 in Fig.

F 4 a diagrammatic view illustratingl i'ecti ying and amplifying the electrical disturbance in the detector created by the leakage of an insulator.

In the drawings like numerals of reference indicate corresponding parts in the different figures.

My improved detector comprises a cylindrical casing 1 of insulating material having a head 2 and a base 3. Connected with the head 2 is the arm 4 which carries a wire brush 5 which is adapted to be contracted with the insulator to be tested. The interior of the casing 1 is divided by means of awpartition 6 into two chambers 7 and 8. ithin the chamber .7 is positioned a variable condenser com rising a stationary member 9 and a movable member 10. This movable member is actuated by means of a threaded stem extending through the head 2` which stem is in electrical contact with the arm 4. The movable member is provided with a pointer 12 extending throu h a slot 13 in the side of the casing 1. T e

casing is provided with a suitable scale with which the ointer 12 co-operates.

Supporte in the chamber 8 are the spark gap posts 14 and 15, preferably having rounded ends. The terminal 14 is stationary', while the terminal 15 is provided with a micrometer adjustment controlled bv means of the knob with a suitable scale, so that a tine adjustlment of the spark gan terminals relative to one another maybe obtained. The movable terminal-15 is in electrical contact with the stem 11 through the spring 17, while the stationary terminal 1 4 is connected by means of themember 18 with the stationary 16, which is provided 20 strument is turbance. l 'f To rectify this electrical disturbance into wireless receiving sets member 9 of the condenser, and also connected by the member 19 with the member 20 carried by the base 3.

Detachably and electrically connected b with the member 20 is the adjustable field slide, which comprises two members21 and 22 adjustable longitudinally relative to one another, which members are mounted within a casing 23 of insulating material. The

w member 22 is actuated by means of an adjusting member 24 which extends through a slot in the casing 23, the casing adjacent the slot being provided with a suitable scale with which the adjusting member co-oper- 16 etes, A suitable handle of any convenient len h will be secured to the casing 23.

referably an instrument in the nature of a hyg'rometerY is used in conjunction with the apparatus above described, which 1nadapted to indicate the moisture condition of the air, and the practice will-be to keep a record of the settings of the condenser, spark gap posts and adjustable field slide at which the instrument is most eilicient for given atmospheric conall ordinary atmospheric conditions.

The detector is used as follows. Having consulted the records for the settin s suitable for the particular type of insu ator to be tested in view of the atmos heric condi- 40 tions then existin the con enser, spark gap and adjustab e slide field are set acoordingly, the brush is contacted with the 1 insulator. If the insulator is porous or cracked and there is a power-leak, the curel rent passes down the arm 4 and stem 1l to the movable mem'ber 10 of the condenser and to the movable post of the spark gap. The condenser and spark ap are so adjustedthat the larger part of t e current I0 wi l have a tendency to jump the spark gap rather than pass through the condenser.

- yThe jumping of the current from post 15 to the post 14 will set up an electrical disan audible signal and amplify same so that it may be heard at a distance I use in conjunction with Athe detector amplifying apparatus which may be ofy a type as used in loud speaker, but asy signals ysuch as made audible by the detector arei usually audible at any setting of radio receiving apparatus,

certain parte as ordinarily used in receiving sets forv tuning" purposes may be in conjunction with a omitted. A suitable circuit is illustrated in Fig. 4 of the drawings.

25 is an antenna, which is positioned close to the detector where it may be affected by the disturbance caused in the detector by leakage from a defective insulator. The antenna is connected in a circuit A in which is located a fixed condenser 26 and a `fixed coil 27, and which circuit is Ialso grounded. A second circuit B containsv a fixed coil 28, a grid leak 29, a rid condenser 30, an audion 31, a loud spea er vunit 32, a rheostat 33. controlling the filament 34 of the audion and the usual A and B batteries 35, 36. The fixed coil 28 is, of course, in inductive relationwith .the coil 27. While the current supplied to the filament 34 is, of course, controlled by the rhepstat 33, it is very important that they si als be amplified to thel same extent un er all conditions, and I find it desirable therefore to include in the amplifying circuitI means for indicatin the current supplied to the filament 34 the A battery 35 and I therefore include in the lead from the battery to the filament an' ammeter or other indicator 37. With this inclusion of lthe indicator 37 in the circuit, I am enabled to maintain a constant condition in the amplifying circuit, and therefore the signals created in the detector will be amplified alwaysto the same extent. f

Various changes in the details of construction of my detector and in my ampliiier may, of course, be made without dearting from the spirit of my invention.

What I claim is:

. 1. In apparatus for locating defective insulators in electric power lines, the combination of a body member; spaced terminals carried by said body memberI and forming between them a spark gap; a member adapted to be contacted with an insulator in electrical connection with one of said terminals; a rod of conducting material in electrical connection with the other terminal,

and adapted to cross the electrostatic field adjacent the insulator being tested; 'and a variable condenser in parallel with said spark gap.

2. In apparatus for locating defective insulators in electric power lines, the combination of a body member; spaced terminals carried by said body member and forming between them, a spark gap; a member adapted to be contacted with an insulator in electrical connection with one of said terminals; and a rod of conducting material in electrical connection with the other terminal` and adapted to cross the electrostatic field adjacent the insulator being tested, said rod being formed of two parts adapted to be telescoped -on one another to vary its length.

3. In apparatus for locating defective insulators in electric power lines, the combinaiscA a slot formed therein tion of a body member; spaced terminals carried by said body member and forming between them a spark gap; a member adapted to be contacted with an insulator in electrical connection with one of said terminals; a rodof conducting material in electrical connection with the other terminal and adapted to crossthe electrostatic field adjacent the insulator being tested, said rod being formed of two parts adapted to be telescoped on one another to vary its length; and a variable condenser in parallel with said slpark gap.

4. n apparatus for locating defective 1nsulators in electric power lines, the combination of a body member; spaced terminals carried by said body' member and forming between them. a spark gap; a member adapted to be contacted with an insulator in electrical connection with one of said terminals; a tubular'handle' of insulating ma-` terial connected with said body member; and a rod of conducting material in said handle, said rod using in electrical connection with the other terminal and adapted to cross the `electrostatic `field beingtesbed. y

5In apparatus for locating defective in- I sulators in electric power lines, the combinw tion of a bod member; spaced terminals carried by sai body member and 'forming between them va spark gap; a member adapted to be contacted with an insulator m electrical connection with one of said terminals; a tubular handle of insulating material connected with said body member; and a rod of conducting material in said handle.

sulator being tested, said rod being formed of two parts adapted to be telescoped on one another'tovary its length, said rod having `a projection thereon and said handle having through which the projection extends. 6. In apparatus for locating de fectlve 1nsulators in electric power lines, the combination of a tubular casing having closed ends; a partition dividing said' casing into upper and lower compartments; a threaded stem extending through'one end of the casing through the upper"` compartment and through .the partition ;'a contact member exmembe tending from said end of the casing and in electrical connection with said stem; a stationary condenser member in said upper compartment; a. movable` condenser r mounted on and adapted to be actuated by said stem; spaced terminals in the Vlower compartment and forming between them a spark gap, one of said terminals hcing1 in electrical communication with the said'stem; and a rod of conducting material in electrical connection with the yother Aadjacent the insulator g Y in electrical connection said rod being in electrical connection with the other terminal and adapted tocross the electrostatic field adjacent the in? ber mounted electrical terminal and adapted to cross the electrostatic field adjacent the insulator being tested.

7. In apparatus for locating defective insulators in electric power lines, the combinationof a tubular casing having closed ends; a partition dividing said casing into upper and lower compartments; a threaded stem extending through one end of the casing through the upper compartment and through 'the partition; a contact member extending from said end of the casing and in electrical connection with said stem; a stationary condenser member in said up er compartment; a movable condenser member mounted on and adapted to be actuated by said stem; spaced terminals in the lower compartment and forming between them a spark gap, one of said terminals being in e ectrical communication with the said stem a rod of conducting material in electrical connection with t and adapted to cross the electrostatic field adjacent the insulator being tested; and a casing of insulating material enclosing said e other terminal rod and forming a handle for the apparatus.

8. In apparatus for locating defective insulators in electric power lines, the combination of a tubular casing having closed ends; a partition dividing -'said casing into upper and lower compartments; a threaded stem extending through one end ofthe casing through the upper compartment and through tlie partition; a contact member exten ing from said end of the casing and c with said stem; a stationary condenser member in said upper compartment; a movable condenser mem on and adapted to be actuated by said stem; spaced terminals in the lower com artment and forminghbetween thema s ar gap, one of said terminals being in e ectrical .communication 'with the! said stem; and

connection with the other terminal and adapted to crossV the a rod of conducting material in,

electfrostatic fieldl loisy adjacent the insulator being tested, said rodibeing formed of two parts escoped on one another to vary itsle'ngth..

9. In apparatus for locating. defective insulators in electric power lines, thecombifnation of a tubular casing havin closed ends; a partition dividing said cas ng 4into upper and lower compartments; a'threaded adapted to be tels/ Istem extending through one end of the casg' ing through the upper'compartmenf and through the partition; a contact-member extending from said end of the;easing and in electrical connection stationary condenser member in said upper compartment; a movable condenser member mounted on and adapted to 'be actuated by said stem; spaced terminals in the lower compartment and forming between them a spark gap, one of said terminals being in electrical communication with the said stem; a rod of conducting material in electrical connection with the other terminal and adapted to cross the electrostatic field adjacent the insulator being tested, said rod being formed of two parts adapted to be telescoped on one another to vary its length,

said last mentioned casing being slotted and themovable portion of said rod having a 10 pro]ection thereon extending through said slot.

Signed at Markdale this 13th day of May, 1926.

THOMAS DUDLY BERRY. 

